Pulp-saving device for paper mills



Oct. 26, 1926.

H. B. WADSWORTH PULP SAVING DEVICE FOR PAPER MILLS Filed Jan. 3. 1924 WWI/AI- ATTORNEY 5 iii) Patented Oct. 26, 1926'.

UNETED STATES l,604,25fi

PATENT ()Fi iCti.

HAROLD 'WADSWOR-TI-I, DECEASED, LATE OF NEW YORK, N. Y.; BY JESSIE B. VJADS- WORTH, EXECUTE/IX,

onn sw YORK, N. Y.

PULP-SAVING DEVICE FOR PAPER MILLS.

Application filed January 3, 1924-. Serial No. 684,184.

The invention relates to a pulp saving olevice for paper mills, and is particularly adapted for saving what would ordinarily be waste fibers carried off with the so-called white water in a paper mill.

It is the principal object of the invention to provide novel means for screening out and saving pulp fibers from white water in a paper mill.

In the preferred form of the invention a tank is provided to which the waste water from a paper mill is conducted. This waste water is ordinarily referred to as white water, since it contains a small percentage of fibers, and heretofore most of these fibers have been lost when the white water was conducted to the drain. A screen is positioned in the tank, which receives the white water, and the tank is preferably of such size as to permit the settling out of some of the fibers. The screen which is immersed in the white water permits the passage of the supernatant liquid, and it is then conducted away, either to shower pipes or to the drain. The deposited and screened out fibers, which remain in the tank together with some of the water constitute what might be termed thickened white water, and is then conducted to beater chests or other machines and mixed with other fibers for use in making paper.

in the drawings which show, for illustrative purposes only, a preferred form of the invention:

Fig. 1 is a partially diagrammatic sectional view, taken substantially in the plane of the line 11 of Fig. 2, of a structure embodying the invention;

Fig. 2 is a sectional view taken substantially in the plane of the line 2-2 of Fig. 1.

In said drawings, 5 indicates a tank or reservoir for receiving the waste or white r-xater in a paper mill. In the form shown the white water is conducted to the tank by means of a conduit 6 emptying into a bay 7. from which an inlet passage 8 leads to the interior of the tank below the normal water level therein. 9 indicates an outlet passage below the level of said inlet passage for conducting the thickened white water from the tank 5 to a storage tank or cistern 10, from which it may later be conducted to beater chests or other machines through the pipe 11.

A screen is positioned in the tank 5 and 1n the present instance the screen is mounted upon and is rotatable with a trunnion 12. Braces or spacers 1313 are secured to the trunnion 12, and beams or purlins 1e are se cured to the braces 13. These parts thus form a frame. I Fine wire gauze 15, of say 120 mesh wire, is stretched on the framework and, if desired, a protecting screen 16 may be secured outside of the fine wire screen in order that any heavy articles or obstructions may not perforate or injure the fine wire screen.

The trunnion 12 is provided with openings or perforations 1717 for a purpose to be lat-er described. One end of the trunnion is closed, as by means of a blank flange 18, and a. suitable shaft 19 is secured thereto. The shaft 19 carries a bevel gear 20, meshing with a drive bevel gear 21 for rotating the trunnion and screen.

The opposite open end of the trunnion 12 is journaled in the opposite side of the tank, and a trough 2 is positioned beneath the open end of the trunnion 12.

The operation of the device is as follows:

Waste water from the various parts of the paper mill, commonly termed white water, is introduced into the tank through the conduit 6, bay 7 and inlet 8. The tank is preferably of such capacity that some of the fibers have time to settle out. The white water prefer ably fills the tank up to a point above the level of the trunnion 12. The water, due to the immersion of the screen, passes through the wire mesh and the fibers which cannot pass the screen are retained in the tank. The liquid, which passes through the screen, then passes into the trunnion 12 through the perforations 17, 17, out the open end thereof and into the trough or conduit 22. This relatively clear water is conducted by the conduit 22 to shower pipes or other parts of the paper mill, or, if an excess of water is present, it may be conducted to the drain. It is, however, desirable wherever possible to reuse this water, so that the small percentage of fiber carried thereby may be utilized in the making of paper.

The fibers which are settled out in the tank 5 or which are screened out by the screen. together with some of the water. constitute what may be termed thickened White water. This thickened white water may pass through the conduit 9 into the storage tank or cistern 10, and from there be lllll conducted by the pipe 11 to beater chests or other machines, where it may be reworked and used.

It has been found in practice that large quantities of fibers may be saved by means of the system above described. It has also been found that, due to the moving or the screen or due to some other reason, libers do not stick to the screen and no trouble is experienced when runnin ordinary white water. However, if water containing a high percentage of pulp should be admitted to the tank, the screen would be likely to clog, and this clogging would be an indication that something was wrong with some part of the paper machine, because of the abnormally large percentage of pulp in the white ater. This device, therefore, acts as a telltale device, so that the workmen will watch the machines and prevent white wa ter of a high percentage of pulp from reaching the tank.

lVhile the invention has been described in some detail it should be understood that tlnspecific form shown is n'ierely illustrative and that many changes may be made within the scope or the appended claim.

I claim:

In a pulp saving device for paper mills in combination, a tank, a rotatable cylinder screen in the upper part thereof with an outlet through the end of said screen for determining a normal water level in the tank. an inlet below the normal water level tor feeding white water into said tank. with a cistern and a passage from the lower n of said tank to said cistern to permit a steady flow 01 pulp from the 'iUl'lllLi. to the latter, with means for ltll(l1';1\\ll1g the pulp from the cistern during the operation oi' the machine to cause the level oi the pulp in the cistern to be below the normal Water level in the tank.

JESSIE B. lVADSlVORTH. Ewccutria: of Estate of Harold Z5. Wadsworth, Deceased. 

